Unlike most smut, this has a plot that makes sense!

The Princess, the Pea, and the Night of Passion (Passion-Filled Fairy Tales) (Volume 1) - Rosetta Bloom

Seriously, there isn't much world building, but the plot does work.  There is also an attempt at romance as well as lust.  It's actually a rather good use of the original story.  Something about the writing isn't quite my taste.  But this was a rather pleasant surprise.